This is a note to let you know that I've just added the patch titled
USB: cdc-wdm: Avoid hanging on interface with no USB_CDC_DMM_TYPE
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-cdc-wdm-avoid-hanging-on-interface-with-no-usb_cdc_dmm_type.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 15699e6fafc3a90e5fdc2ef30555a04dee62286f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= <[email protected]>
Date: Fri, 20 Jan 2012 01:49:57 +0100
Subject: USB: cdc-wdm: Avoid hanging on interface with no USB_CDC_DMM_TYPE
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From: Bjørn Mork <[email protected]>
commit 15699e6fafc3a90e5fdc2ef30555a04dee62286f upstream.
The probe does not strictly require the USB_CDC_DMM_TYPE
descriptor, which is a good thing as it makes the driver
usable on non-conforming interfaces. A user could e.g.
bind to it to a CDC ECM interface by using the new_id and
bind sysfs files. But this would fail with a 0 buffer length
due to the missing descriptor.
Fix by defining a reasonable fallback size: The minimum
device receive buffer size required by the CDC WMC standard,
revision 1.1
Signed-off-by: Bjørn Mork <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/class/cdc-wdm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -57,6 +57,8 @@ MODULE_DEVICE_TABLE (usb, wdm_ids);
#define WDM_MAX 16
+/* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */
+#define WDM_DEFAULT_BUFSIZE 256
static DEFINE_MUTEX(wdm_mutex);
@@ -636,7 +638,7 @@ static int wdm_probe(struct usb_interfac
struct usb_cdc_dmm_desc *dmhd;
u8 *buffer = intf->altsetting->extra;
int buflen = intf->altsetting->extralen;
- u16 maxcom = 0;
+ u16 maxcom = WDM_DEFAULT_BUFSIZE;
if (!buffer)
goto out;
Patches currently in stable-queue which might be from [email protected] are
queue-3.0/usb-cdc-wdm-use-two-mutexes-to-allow-simultaneous-read-and-write.patch
queue-3.0/usb-cdc-wdm-avoid-hanging-on-interface-with-no-usb_cdc_dmm_type.patch
queue-3.0/usb-cdc-wdm-call-wake_up_all-to-allow-driver-to-shutdown-on-device-removal.patch
queue-3.0/usb-cdc-wdm-updating-desc-length-must-be-protected-by-spin_lock.patch
queue-3.0/usb-cdc-wdm-better-allocate-a-buffer-that-is-at-least-as-big-as-we-tell-the-usb-core.patch
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